KJ Apa was dapper as ever in a patterned suit jacket that he wore without a tie. Instead, he opted to button his crisp white shirt up to the top.

See the "Riverdale" cast at the 2017 AMAs:

Camila Mendes was also there, looking absolutely stunning in a plunging nude gown with intricate yellow embroidery. The actress opted for no accessories and wore her gorgeous dark locks down to her shoulders.

Lili Reinhart wore a unique, asymmetrical black dress with sheer paneling on her torso. She finished the look with platform sandals and a chic updo. It was Madelaine Petsch, though, who won the "Riverdale" style contest in her plunging black gown with sheer paneling and feathery accents. The look perfectly complemented her porcelain skin, and she finished off the ensemble with a bun.